In principle, asking a question on multiple sites is fine, since each site has a different community that will probably answer the question in a different way. If the user is consciously choosing to cross-post for that reason, as evidenced by them taking the time to phrase the question differently on each site, then it's fine. I've even told people to do this before.
But then there are about the lazy, spammy kind of cross-posts where a user is clearly copy and pasting their entire question from one SE to another simply because they think more posts equals more attention. Often, these cross-posts are on-topic on both sites, and poorly written but probably salvageable, so none of the usual close/migration reasons apply (which is why this isn't a duplicate of all the existing meta questions about cross-posting). All we can do is downvote if the question itself is bad and add a comment that cross-posts are frowned upon.
What is the right way to handle these posts?
- Are both communities obliged to help? Since it is exactly the same question that would mean a lot of duplication of effort.
- Should the site that's "slightly less on-topic" close or ignore it and let the "more on-topic" site deal with it? I fear this might be our de facto behavior on PSE right now.
- Or should we have some auto-detection that simply looks at what the user has already posted today and warns him that we dislike cross-posting? From what I've seen these cross-posts are from the kind of newbie that might actually listen to a warning.
